The problem is you are confusing people...The "Mid-Pipe" is after the J-pipe and contains a catalytic converter..
What you keep calling the mid-pipe, is not the mid-pipe and contains a "resonator" only. You want to find a cat to axle section right and match it to a different brand axle-back..right??? That's fine, but a bit "Frankenstein"...the flanges for an axle-back only will be made to match up with the OEM flanges...so you are not guaranteed that they will match up with your cheap EBAY piping...
And the OEM piping is 1.75" inner diameter....NOT 2.25"